city water chlorinated
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Chlorine itself will leave the water during an over night stand in an open container.
Chloramine (produced when chlorinated water is treated with ammonia at the plant) is much more stable which is the reason it is used. It takes 10 days of standing for chloramine to be reduced to an acceptable level.
Chlorine can be removed immediately by boiling.
It takes several hours of boiling to remove chloramine.
Chlorine and chloramine can both be removed by filtration through activated carbon.
Chlorine and chloramine can both be removed by treatment with metabisulfite. One Campden tablet per 20 gallons of water is usually sufficient. This is the preferred method both because of speed and simplicity.
Chloramine (produced when chlorinated water is treated with ammonia at the plant) is much more stable which is the reason it is used. It takes 10 days of standing for chloramine to be reduced to an acceptable level.
Chlorine can be removed immediately by boiling.
It takes several hours of boiling to remove chloramine.
Chlorine and chloramine can both be removed by filtration through activated carbon.
Chlorine and chloramine can both be removed by treatment with metabisulfite. One Campden tablet per 20 gallons of water is usually sufficient. This is the preferred method both because of speed and simplicity.
Not precipitate, volatilize. That stability that AJ mentions, makes chloramine tougher to remove. Chlorine is easy to remove with activated carbon, but you have to reduce the flow rate drastically to get good chloramine removal with that treatment.
If you don't know which disinfectant is in your water, the metabisulfite treatment is easy and effective. Chlorophenols are a huge defect in beer flavor, so do take measures to remove all disinfectants from tap water prior to any use in brewing.
If you don't know which disinfectant is in your water, the metabisulfite treatment is easy and effective. Chlorophenols are a huge defect in beer flavor, so do take measures to remove all disinfectants from tap water prior to any use in brewing.
AJ, the results in the following report by you indicated that the chloramines had a boiling half life of 10 minutes (or less). Please explain. Thanks.
http://hbd.org/ajdelange/Brewing_articles/BT_Chlorine.pdf
To be honest I didn't remember it as being that short. Anyway, half life is the amount of time it takes for the concentration to drop to half of what is is originally. The logarithm of the concentration thus decreases by log(2) = 0.3010 in one half life. If you start with a chloramine concentration of 3 mg/L (log(3) = .4771 and you want it reduced to 0.1 mg/l (log(.1) = -1 you need to reduce the log by 1.4771 and that takes 1.4771/0.301 = 4.9 half lives. At a half life of 10 minutes that's 49 minutes. If you want to go to 0.01 mg/L (which I guess is pretty complete removal) you will need another log unit for a total of 2.477 corresponding to 2.477/.3010 = 8.22 half lives or 82 minutes.
Guess I should have said about an hour instead of hours and now that I think about it that seems right,
Guess I should have said about an hour instead of hours and now that I think about it that seems right,
Thanks. Considering there was an even shorter half life that inexplicably showed up, the chloramine concentration is less than 1% of it's original after a standard 60-minute boil.
For brewing purposes I'd consider that to be complete removal. I've used campden tablets in the past, but I think I'm not going to replace them when they are gone.
Don't forget to consider fuel costs and the time element.
If I'm already doing an hour boil, there's no additional cost? I guess I'm trying to convince myself that chloramines are removed during a normal brewday.
That is not the boil for the wort, its a separate pre-boil of the water alone to drive off the chlorine or chloramine. Once wort sugars contact the chlorine or chloramines, they complex and are no longer volatile. Then its impossible to get them out. You are then left with chlorophenols in your beer.
Ah! OK, thanks. I wondered if the wort complicated things. Back to the tablets.
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